A rotary press is equipped with an automatic web leading device for automatically leading a web from a web feed section to a printing section and a folding section along a normal web-leading path. Presently, in rotary press manufacturers, the development of an automatic web leading device capable of coping with the entire web-leading path including a turn bar section and a bay window device has been almost completed. As such an automatic web leading device, there has been known one type designed such that a guide rail is arranged along a lateral edge of a web-leading path, and a web-pulling slider unit connected to a leading end of a web is slidingly moved along the guide rail by drive means. While drive systems for the web-pulling slider unit or branch/junction mechanisms for the guide rail in automatic web leading devices of this type are slightly different from each other, they are much alike and the difference results from structural difference in the web-pulling slider units. In other words, a major feature of the automatic web leading device in each of the rotary press manufacturers is the web-pulling slider unit itself.
For example, the following Patent Publication 1 discloses a web-pulling slider unit intended to be slidingly moved inside a guide rail with a reduced friction coefficient relative to the guide rail so as to suppress wearing. Specifically, this slider unit comprises a plurality of spherical members each made of a material having a low friction coefficient, and a plurality of joint tubes each formed of a stainless steel pipe. The spherical members and the joint tubes are alternately arranged and tied in a row using a wire inserted through center holes formed in the spherical members and the joint tubes.
In the web-pulling slider unit disclosed in the Patent Publication 1, the joint tube has opposite ends each formed in a conical concave shape allowing an adjacent one of the spherical members to be held on an axis of the joint tube. That is, the web-pulling slider unit is designed to allow only respective junctions between the spherical members and the joint tubes to be bent and twisted. Thus, while the web-pulling slider unit can be slidingly moved in conformity to a curved portion and a twisted portion in a web-leading path to a certain degree, it is difficult to fully conform to a configuration of an adjust roller section having a large winding angle and a turn bar section having complicated curve/twisting, causing a problem about difficulty in stably pulling and guiding a web.
[Patent Publication 1] Japanese Patent Laid-Open Publication No. 05-193096